Researchers working to protect state's largest crop from disease

Virginia Tech's agricultural scientists are taking additional steps in the plan to protect the commonwealth's soybean crop from major yield reductions caused by Asian soybean rust, an aggressive fungal disease.

"Soybean rust has not been detected in Virginia," said David Holshouser, soybean agronomist at the Tidewater Agricultural Research and Extension Center at Suffolk. The plan was put into action because the U.S. Department of Agriculture's Animal and Plant Inspection Service (APHIS) announced on Wednesday, Nov. 10, that the disease had been identified in Louisiana.

Soybeans are an important agricultural product. It is the largest row crop in the state, and this year, Virginia soybean producers are harvesting 490,000 acres with an average yield of 36 bushels per acre. Production is expected to total 17.6 million bushels, up 8 percent from last year. The crop's farm gate value has ranged from $75 million to $100 million annually. This year the farm gate value should be in the range of $80 million.

Virginia soybean producers became concerned about the devastation caused by the disease in Brazil where it now infests more than 90 percent of the soybean crop. The Virginia Soybean Rust Task Force prepared a Virginia Response and Action Plan last summer, said Jim Riddell, Virginia Cooperative Extension associate director for Agriculture and Natural Resources. The task force includes representatives from the Virginia Department of Agriculture and Consumer Services, Virginia Soybean Association and Board, Virginia Farm Bureau Federation, Virginia Crop Production Association, Farm Credit, and the USDA Risk Management Agency as well as Virginia Tech.

During the 2004 growing season, Virginia Tech, used funding from the Virginia Soybean Board, to conduct an extensive monitoring program. Fields throughout most of Virginia's soybean production region were scouted on a biweekly basis from June through September, and soybean rust was not detected. The 2004 soybean crop has already matured and is being harvested.

"To continue to protect Virginia soybean producers, Virginia Tech conducted in-depth training in September for more than 80 'first detectors,' who are the eyes and ears of a monitoring program," said plant pathologist Erik Stromberg, interim head of the university's Department of Plant Pathology, Physiology, and Weed Science. These "first detectors" are Virginia Cooperative Extension agents, certified crop advisers, crop consultants, and other agronomists.

"The chance of soybean rust spreading to Virginia in 2005 will depend on whether or not the fungus is found in other areas of the United States, and whether it will survive the winter in those locations," Holshouser said.

It is currently thought that the fungus would over-winter on alternative hosts (such as kudzu, and winter vetch) in southern Florida or Texas. Unless the fungus is found in those areas, it would have to be reintroduced from South America or the Caribbean Basin before it could affect Virginia.

Stromberg added that the state of Virginia has applied for an emergency Section 18 pesticide label for several fungicides to control soybean rust. These plus three currently available fungicides can be used during 2005 if soybean rust is detected in Virginia or threatens Virginia's soybean production.

Researchers also are working to develop soybean cultivars that are resistant to the Asian rust, but fungicides will be the primary line of defense until resistant cultivars become available.

"Our action plan describes our educational goals, our pre- and post-confirmation communication plan, and how Virginia will respond once rust is confirmed in Virginia or other parts of the United States," Holshouser said.

"Virginia soybean growers need to stay informed about this potential problem," Holshouser said. If any growers suspect that there is rust, they should contact the local Virginia Cooperative Extension agriculture and natural resources agent or a certified crop adviser. That person will take a sample of the suspected area to the nearest Virginia Diagnostic Center. If experts at the diagnostic center suspect rust, the sample will go on to USDA-APHIS for confirmation.

"Unfortunately, these models indicate the Mid-Atlantic and southeastern states are at most risk," said Pat Phipps, plant pathologist at the Tidewater center. "Wind patterns, our warm and humid climate, and significant acreage of soybeans and other hosts make Virginia an ideal location for the disease to become established."